Hi, Elena. The needle used for iv's is a tiny one, much like they ise in acupuncture. Once the needle is in and the tubing is taped on, you don't feel it. As unpleasant as it is, it's a necessary item to your treatment and care.
We can't talk you out of being afraid. You have to work on that yourself by monitoring your inner self-talk and by challenging your fears. You know the IV is for your own good. Talk to yourself now with some calming and reasoned thoughts. Cognitive behavior is what this site's about. Maybe you can try a little now?